1. Field of the Invention
This invention relates to lettering elements, including figures and designs, cut from pigmented flexible plastic sheet material; and to the process of applying them in an aligned group, as on commercial awnings and other impervious surfaces.
2. Description of Related Art
U.S. Pat. No. 3,660,212 to Liebe discloses a process for making plastic lettering material comprising a paper release sheet, a vinyl display layer, and an encapsulating thermoplastic adhesive sheet bonded to the surface of the display layer opposite the release sheet. For application of a design or lettering onto a woven or knitted garment or other permanent substrate, separate lettering elements are die-stamped from such sheet material and individually positioned and heat bonded (in effect ironed) onto the surface of the substrate, the heat liquefied adhesive creating a mechanical bond by flowing into and curing within the interstitial spaces of the porous surface of the substrate.
The minimal adhesion of the vinyl display layer to the release sheet may allow the edges of individual lettering elements to detach and curl away from the release sheet. Since both the display layer and release sheet are cut through at their edges, such curling is readily detectable and correctable during application of an individual lettering element, and has not been a serious deterrent to the use of the lettering material.
No prior art known to Applicant discloses lettering material whose display layer adheres to a release sheet with sufficient tenacity to permit the release sheet to remain intact and serve as a carrier for an assemblage of individual lettering elements cut, from an adhesive side, through the adhesive and display layers to be together mounted on a substrate.
For a somewhat similar purpose, U.S. Pat. No. 4,786,349 to Mahn discloses the concept of a continuous layer of adhesive cast onto a release sheet, onto which indicia have been roll printed, using thermosetting ink. For application of these indicia to a permanent substrate, the release sheet is to be removed, the unprinted surface of the adhesive positioned onto the surface of the substrate, blotting paper placed over the printed surface of the adhesive, and heat and pressure sufficient to liquefy the adhesive applied. That portion of the liquefied adhesive not beneath indicia is to be absorbed by the blotting paper, and removed from the substrate. It is not known by Applicant if this method proved to be practical.